This database, collected at the Children’s Hospital Boston, consists
of EEG recordings from pediatric subjects with intractable seizures.
Subjects were monitored for up to several days following withdrawal of
anti-seizure medication in order to characterize their seizures and
assess their candidacy for surgical intervention.

Recordings, grouped into 23 cases, were collected from 22 subjects (5 males,
ages 3–22; and 17 females, ages 1.5–19). (Case chb21 was obtained 1.5
years after case chb01, from the same female subject.) The
file SUBJECT-INFO contains the gender and
age of each subject. (Case chb24 was added to this collection in
December 2010, and is not currently included in SUBJECT-INFO.)

Each case (chb01, chb02, etc.) contains between 9
and 42 continuous .edf files from a single subject. Hardware
limitations resulted in gaps between
consecutively-numbered .edf files, during which the signals
were not recorded; in most cases, the gaps are 10 seconds or less, but
occasionally there are much longer gaps. In order to protect the
privacy of the subjects, all protected health information (PHI) in the
original .edf files has been replaced with surrogate
information in the files provided here. Dates in the
original .edf files have been replaced by surrogate dates,
but the time relationships between the individual files belonging to
each case have been preserved. In most cases, the .edf files
contain exactly one hour of digitized EEG signals, although those
belonging to case chb10 are two hours long, and those
belonging to cases chb04, chb06,
chb07, chb09, and chb23 are four hours
long; occasionally, files in which seizures are recorded are shorter.

All signals were sampled at 256 samples per second with 16-bit
resolution. Most files contain 23 EEG signals (24 or 26 in a few
cases). The International 10-20 system of EEG electrode
positions and nomenclature was used for these recordings. In a few
records, other signals are also recorded, such as an ECG signal in the
last 36 files belonging to case chb04 and a vagal nerve
stimulus (VNS) signal in the last 18 files belonging to
case chb09. In some cases, up to 5 “dummy” signals (named
"-") were interspersed among the EEG signals to obtain an easy-to-read
display format; these dummy signals can be ignored.

The file RECORDS contains a list of all
664 .edf files included in this collection, and the file
RECORDS-WITH-SEIZURES
lists the 129 of those files that contain one or more seizures. In
all, these records include 198 seizures (182 in the original set of 23
cases); the beginning ([) and end (]) of each
seizure is annotated in the .seizure annotation files that
accompany each of the files listed in RECORDS-WITH-SEIZURES.
In addition, the files named chbnn-summary.txt
contain information about the montage used for each recording, and the
elapsed time in seconds from the beginning of each .edf file
to the beginning and end of each seizure contained in it.

Relevant Publications

In addition to the thesis cited at the top of this page, these publications
describe a patient-specific seizure onset detection algorithm, and the first
of them describes its evaluation using this database:

Acknowledgments

A team of investigators from Children’s Hospital Boston (CHB) and the
Massachusetts Institute of Technology (MIT) created and contributed this
database to PhysioNet. The clinical investigators from CHB include Jack
Connolly, REEGT; Herman Edwards, REEGT; Blaise Bourgeois, MD; and S. Ted
Treves, MD. The investigators from MIT include Ali Shoeb, PhD and Professor
John Guttag.

Contact

For further information about this database, please contact Ali Shoeb, PhD
(ashoeb at mit dot edu).